Exit Sign

Exit sign self-testing system

Exit Sign Abstract
A system for testing the electrical integrity of an illuminated exit sign alternately powered by a battery, rechargeable from a source of alternating current power. The system includes an alarm for indicating an electrical failure, precluding the illumination of the exit sign. A circuit tests the presence of battery electrical power for illuminating the exit sign. In addition, the circuitry periodically tests for the provision of adequate battery power to achieve the same function. Moreover, the system periodically tests and retests for adequate recharging of the battery during a preselected period of time and includes an alarm for indicating failure of the recharging system.

Exit Sign Claims
What is claimed is:

1. A system for testing the electrical integrity of an exit sign illuminated by a lamp, alternately powered by a battery rechargeable from a source of AC power and powered by the AC power source; comprising:

a. alarm means for indicating an electrical failure precluding illumination of the exit sign;

b. means for periodically testing for the presence of battery electrical power to illuminate the exit sign, said alarm means indicating the absence of battery power;

c. means for periodically testing for the provision of adequate battery power to illuminate the exit sign, said alarm means indicating inadequate battery power;

d. means for periodically testing for adequate recharging of the battery during a preselected period of time, said alarm means indicating the failure of the recharging of the battery; said means for periodically testing for the presence of the battery power, said means for periodically testing for the provision of adequate battery power, and said means for periodically testing for adequate recharging of the battery further comprise means for transferring the source of illumination of the exit sign between the AC source and the battery; and

e. means for periodically testing for the existence of the lamp and for the operation of said means for transferring the source of illumination of the exit sign between AC source and the battery, including a detector for a ripple voltage associated with the AC source.

2. The system of claim 1 in which said alarm means comprises a visual unit having distinctive signals to selectively indicate the absence of battery power, inadequate battery power and failure of the recharging of the battery.

3. The system of claim 1 in which said detector comprises a control circuit, said control circuit includes a comparator for detecting the presence of said ripple voltage at the output of said comparator.

4. The system of claim 3 in which said alarm means comprises a visual unit having distinctive signals to selectively indicate the absence of battery power, inadequate battery power, and failure of the recharging of the battery.

5. The system of claim 4 in which said alarm means comprises a light emitting diode.

6. The system of claim 4 in which said alarm means further comprises a bicolor light emitting diode.

Exit Sign Description
BACKGROUND OF THE INVENTION

The present invention relates to a novel and useful system for testing the electrical integrity of an illuminated exit sign.

Illuminated exit signs are required by law to be placed in edifices to indicate egress from a structure as a matter of convenience and during periods of emergency. It is, thus, important that such exit signs be reliable, being provided with a constant supply of electrical power to maintain illumination of the exit signs at all times. Along these lines, it is imperative that the integrity of the electrical system of an illuminated exit sign be tested at selected intervals to ensure that power is always available to the exit sign under all conditions. That is to say, the existence of a battery, the integrity of the battery, the charging system for the battery, and the like, must constantly be determined.

In the past, many testing procedures for illuminated exit signs have been accomplished manually by roving personnel. Written records must also be kept of such visual inspections and tests for review by legal entities having jurisdiction over such matters. Recently, many rules and regulations have permitted the use of self-testing and self-diagnostic illuminated exit signs operated by a battery, in conjunction with limited visual inspections by personnel. Thus, it is advantageous to provide illuminated exit signs that are capable of accomplishing such self-tests.

U.S. Pat. Nos. 3,384,886, 4,088,986, and 4,544,910 describe emergency lighting and exit sign systems that include indicators showing the existence of stand-by power, the proper level of voltage of the stand by power and the integrity of a battery.

U.S. Pat. No. 4,199,754 shows a circuit for an emergency lighting and fire detection system which latches an emergency light in an off position indicating that a low voltage condition exists in the battery power source.

An exit sign which is capable of continually self testing and retesting source of battery power and recharging system for such battery would be a notable advance in the emergency lighting field.

SUMMARY OF THE INVENTION

In accordance with the present invention a novel and useful system for the testing of the electrical integrity of an illuminated exit sign is herein provided.

The system of the present invention utilizes an exit sign that is alternately powered by a battery or a source of alternating current, which also is capable of recharging the battery. The exit sign includes alarm means for indicating an electrical failure which would preclude the illumination of the exit sign. Such alarm means may be a bi-color indicator which is capable of emitting a steady light or a blinking light, as the case requires.

Circuit means is included in the exit sign for periodically testing the presence of a battery at certain time intervals. In other words, the absence of battery power is determined during intervals. In addition, means is provided for periodically testing the level of battery power which is adequate to illuminate the exit sign. The alarm means indicates either situation.

Further, the existence of source of lighting, such as an LED light strip is also determined by the circuitry of the present invention. Again, the alarm means would indicate by a certain color of light or a particular pattern of light the existence or non existence of the LED strip. In one embodiment of the invention, signal voltage of a peculiar pattern is detected by comparator which is indicative of the presence of the LED strip. If such peculiarly patterned signal disappears, the alarm means would indicate the absence of an LED strip.

Besides the existence and failure of the battery source for the exit sign, the system of the present invention periodically tests the charging system for the battery. That is to say, although a battery may pass its end-of-life test, a subsequent test within a short period of time after charging the battery may indicate a failure. Usually this is interpreted as a charging system failure.

During most of the self-testing activities of the system of the present invention a transfer function takes place in which illumination of the exit sign occurs as a result of exchanging the alternating current source for the battery source. The system of the present invention also checks the integrity of such transfer system, which is the basis of many of the tests herein above described. In other words, the presence of the battery, power level of the battery, and recharging of the battery of the exit sign will require the functioning of the transfer system between the AC and DC power sources.

It may be apparent that a novel and useful system for the testing of the electrical integrity of an illuminated exit sign is herein provided.

It is therefore an object of the present invention to provide a system for testing the electrical integrity of an illuminated exit sign which is capable of testing for the existence of a battery source of power, an adequate level of battery voltage, and recharging system for the battery.

A further object of the present invention is to provide for a system for testing the electrical integrity of an illuminated exit sign which is capable of retesting the battery charging system and a battery end-of-life function after a specific interval following the initial tests of these functions to eliminate false signals.

A further object of the present invention is to provide a system where the testing of the electrical integrity of an illuminated exit sign eliminates many manual tests and reduces the cost of maintaining exit signs in buildings.

Yet another object of the present invention is to provide a system for the testing of the electrical integrity of an illuminated exit sign which includes an alarm indicator having multiple visual cues which are easily interpreted by the user.

A further object of the present invention is to provide a system for the testing of the electrical integrity of an illuminated exit sign which is highly reliable in an emergency situation.

The invention possesses other objects and advantages especially as concerns particular characteristics and features thereof which will become apparent as the specification continues.